Electric furnace



Feb. 23 ,1926. l 1,574,108

' F. PETERSON ELECTRI C FURNACE Filed March 16 1925 any,

4 a l' /z 2@ INVEN TOR.

Patented Feb. 23, 1926..

- UNITED STATES 1,514,108 PATENT OFFICEel FREDOLF J'. `IETERSON, (OF DETROIT, MICHTGAN.-

l ELECTRIC FUBNACE.

. V.Application le March 16, 1925. Serial No. 15,795.

To all whom it may concern:

Be it known that I, FREDOLF J. PETERSON, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

This invention relates to an electric furnace,and has for its object the provision of heating elements which will more eiici'ently and thoroughly heat a piece of stock placed in the furnacef This furnace construction involves an improved manner of suspending a heating element from the ceiling of the furnace, and it also embraces the combinaf tion of several heating elements so arranged as to uniformly heat all surfaces of the stock.

In order to eiiiciently heat a length of bar stock to a temperature where the same may be upset to form bolts, gears or other light products, it is quite essential that the stock be heated to an even temperature throughout by a means that is easily controlled, quick -in action, and :which requires a minimum amount of attention from the operator.

In the drawings:

Fig. 1i is a vertical section through a furnace.

Fig. 2 is a section on the line 2 2 of Fig. 1, showing how my improved heating elements surround -the metal stock to be heated.

Fig. 3 is a section on the line 3 3 of Fig. l, showing thel upper heating element which is suspended from the ceiling.

Figs. 4 and 4;* are sections taken on the lines 4.-4 and PL-4 of Fig. 3, showing how the upper heating element is suspended from the ceiling. A

Fig. 5 is a section on the line 5-5 of Fig. 1, showing how the heating element may be secured to the wall.

" A furnace a is built u of fire brick or other' refractory4 material) and thoroughly insulatesthe 'furnace chamber b from the outside. It is the usual practice to provide a wall c of kiesel hr -or infusorial earthl about this fire bric construction ,and then surround the entire furnace with a metal casing d. The metal casing is provided with a lurality of small'door openings e through Eichmetal stock f, here shown 1n the drawings as bar stock, may be inserted into the heatin chamber of the furnace. Suspended from t e ceiling of the furnace is a resistance heating element g which is usually composed of nickel and chromium, which is an alloy that is especially adapted for large heating units. This heating unit is looped back and forth, as shown in Fig. 3, the long runs of said unit being longitudinally grooved as at 71,. A cross section of this heating unit is clearly shown in Fig. 2, and it will be noticed that this groove L- is approximately a half circle.

This heating element is suspended fromv the ceilin in a novel manner. Built into the fire brick above the ceiling is a hanger z' which isprovided with a dove-tail portion j atxthe lower end. The heating elements areprovided with the dove-tail sockets 76 at the rear and the sockets fm. at the forward end. To assemble and suspend this heating element from the ceiling it is merely necessary to slide the heating unit into the furnace and slip the dove-tail socket at the rear of the heating unit over the dovetail projection at the rear by moving the heating elementforward. This will also e11- gage t e dove-tail socket m at the front end of the heating unit over the dove-tail projection at the forward end of the heating, chamber. Another A heating unit complementary to the heating unit suspended from the ceiling is located immediately below and rests on brackets n on the floor of the heating chamber.

It will be seen from observing Fig. 2 that the grooves running longitudinally in the long runs of the looped heating unit, each of which is approximately a half circle, forms substantially a complete circle about the bar stock which is inserted between these twoheatmg elements. It will be observed that the effective heating surface of the heating units is substantially the same distance from all points in the surface of the bar stock. This will create a uniform heating intensity on all points of the surface of the stock and heat the same uniformly. In addition with this semi-cylindrical construction of the heating unit, we obtain a maximumfamount of heat dispersion for heatin the stock.

At t erear of the heating chamber I suspend or han a heating element o to the wall of the cham er Aby providing the dove-tailed' end of the furnace, but it is not essential that these be the same, as any other form of heating unit could be utilized in the end wall, as its purpose is to throw the heat against the end of the bar stock so as to heat the end of the stock.

With such a construction I find that the maximum amount of heat units are absorbed by the stock, due to the fact that the heating elements practically surround the stock and direct the heat radially against the stock, the heating surface of the heating units being spaced approximately the same distance from all points of the stock.v Obviously square stock or other cross sections of stock could be inserted between these same heating elements, or the grooves in said heating elements could be V-shaped or formed of other angles. For instance, if it were desired to heat a piece of stock which was Octagon in shape, the grooves in each element could be angularly grooved to correspond to four sides of the Octagon while the remaining sides of the -Octagon could be taken care of in the other heating element.

What I claim is:

4'1. In an electric furnace, the combination of a heating chamber, and resistance heating elements supported therein in close proximity to each other but permitting the positioning of stock to be heated therebetween, whereby approximately the entire surface of said stock is spaced substantially equidistant from said heating elements to expose the entire surface of the stock to approximately the same intensity of heat.

2. In an electric furnace, the combination of a heating chamber, and resistance rheating elements supported therein in close proximity to each other and provided with grooves running longitudinally of said heating elements, said heating elements so positioned and arran ed as to locate the grooves opposite an parallel to each other to provide a space in which a piece of stock may be positioned in spaced relatiomwith the walls of said heatin elements, thereby permitting the heating e ements to substantially surround said ieee of stock. f

3. In an electric urnace, the combination of a heating chamber and resistance heating elements supported therein in close proximity to each other and each provided with a semi-circular groove running longitudinally thereof, the said heating elements arranged in such a position as to locate the semi-circular grooves opposite and parallel to each other to provide substantially a complete circular recess for receiving a piece of bar stock to be heated, said stock spaced from the surfaces of said heating elements to permit the stock to be heated by radiant `ieat.

4. In an electric furnace, the combination of a heating chamber and resistance heating elements supported therein in close proximity to each other, each heating element looped back and forth to provide a plurality of straight runs in which are located longitudinal grooves, the said heating elements positioned to locate the said grooves opposite and parallel to each other to provide a recess in which the stock may be p0- sitioned and arranged to substantially surround said piece of stock.

5. A heating element for an electric furnace, comprising a bar of resistance material provided with a longitudinal U-shaped groove running lengthwise of said baiin which a piece of stock may be positioned in spaced relation to be heated.

6. A heating element for an electric furnace, comprising a bar of resistance material provided with a semi-circular groove running longitudinally thereof in which a piece of bar stock may be positioned in spaced relation to be heated by radiant heat.

fr'. A heating element for an electric furnace, comprising a relatively long bar of resistance material which is looped back and forth to provide a plurality of runs, each having a groove running longitudinally thereof in which a piece of bar stock may be positioned to be heated.

8. A heating unit for an electric furnace, comprising a pair of heating elements, each provided with a groove running longitudinally thereof, said heating elements positioned in close proximity to each other and arranged to match up the grooves to provide a recess in which apiece yof stock may be centrally positioned and substantially surrounded by said heating elements, but in spaced relation therewith.

9. In an electric furnace, the combination of a heating chamber, resistance heating elements supported from the Hoor and ceiling of said furnace and arranged to lie in close proximity -to each other but permitting a piece of stock to be positioned therebetween, and an electric resistance heating element secured to the end wall of said furnace for heating the end of said stock while the other heating units heat the body portion of said stock.

10. In an electric furnace, the combination of a heating chamber provided with a pair of heating elements which are positioned in close proximity to each other and parallel to each other and so spaced apart as to permit a piece of stock to be inserted therebetween to be heated, and one or more additional heating units at the rear of the furnace arranged to direct the heat forwardly onto the end of said stock which is being heated.

11. In an electric furnace, the combination of a heating chamber provided with a i ceiling, hangers supported from said ceiling tion projecting Within the heating chamber and serving as guides, and a heating element provided with dove-tailed sockets arranged to lbe engaged by said dove-tailed proJections carried by the' hangers for the purpose of s.upporting said heating element from the cellmg.

that portion of the bar at the ends of the loops being attened out to remove the side walls ofnthe grooves to permit a piece of bar stock to be inserted between said heating elements and positioned in said grooves and to be substantlally surrounded by said heating elements. v

13. A heating element for an electric furnace, comprising aber of resistance material provided'with a longitudinal groove on one side for the purpose of providing av relatively greater surface area for the ra 1ation of heat on one side of the heating element than on the other side.

14. A heating element for an electric furnace, comprising a bar of resistance material provided on one side thereof with substantially a U-shaped groove running length- Wise of said bar for the purpose of providing a relatively greater surface area for the radiation of heat on one Iside of the heating element than on the other.

15. A heating element for an electric furnace comprising a relatively long bar of resistance material which is looped back and forth to provide a looped heating ele ment, said heating element provided with a groove on one side running lengthwise of said bar for `the purpose of providing a relatively greater surface area for the radiation of heat on: one side of the heating element than on theother.

In testimony 'whereof I have aixed my signature.A .1

i FBEDQLF J.' PETERSON. 

